REUTERS - Boxers who fail doping tests should be banned for life, according to Britain's IBF world heavyweight champion Anthony Joshua.

Joshua became the first boxer to hold the Olympic super-heavyweight crown and a version of the world heavyweight title simultaneously with his triumph at the O2 Arena in April, a few miles from where he won gold at the London 2012 Games.

The boxer said he has undergone random checks twice by Britain's anti-doping agency in the last two weeks, ahead of his first defence of the title against American Dominic Breazeale in London on Saturday.

"If there is anything you're taking to gain an advantage over your opponent, 100 per cent you should be banned for life," Joshua, who won the world heavyweight crown in only his 16th professional fight in April, told British media.

"It is happening out there. I've always been into hard work and being aware of what you're taking. I've been tested twice in these last couple of weeks. One was 6am and one was 10pm.

"You have to let them know in advance where you're going to be sleeping, where you're going to be training and what you're going to be doing."